1. Field of the Invention
The invention relates to a panel structure of a surface-discharge-scheme alternating-current-type plasma display panel.
The present application claims priority from Japanese Applications No. 2001-213846, No. 2001-218297 and No. 2002-13320, the disclosures of which are incorporated herein by reference for all purposes.
2. Description of the Related Art
In recent times, a surface-discharge-scheme alternating-current-type plasma display panel has been received attention as a slim, large sized color screen display, and has become commonly used in ordinary households and the like.
FIG. 34 to FIG. 36 are schematic views of a conventional structure of the surface discharge-scheme alternating current-type plasma display panel. FIG. 34 is a front view of the conventional surface-discharge-scheme alternating-current-type plasma display panel. FIG. 35 is a sectional view taken along the Vxe2x80x94V line of FIG. 34. FIG. 36 is a sectional view taken along the Wxe2x80x94W line of FIG. 34.
In FIGS. 34 to 36, the plasma display panel (hereinafter referred to as xe2x80x9cPDPxe2x80x9d) includes a front glass substrate 1, serving as the display surface of the PDP, having on its back surface, in order, a plurality of row electrode pairs (Xxe2x80x2, Yxe2x80x2), a dielectric layer 2 covering the row electrode pairs (Xxe2x80x2, Yxe2x80x2), and a protective layer 3 made of MgO and covering the back surfaces of the dielectric layer 2.
The row electrode Xxe2x80x2 and the row electrode Yxe2x80x2 of each row electrode pair (Xxe2x80x2, Yxe2x80x2) are respectively constructed of transparent electrodes Xaxe2x80x2, Yaxe2x80x2 each of which is formed of a transparent conductive film of a larger width made of ITO or the like, and bus electrodes Xbxe2x80x2, Ybxe2x80x2 each of which is formed of a metal film of a smaller width assisting the electrical conductivity of the corresponding transparent electrode.
The row electrodes Xxe2x80x2 and Yxe2x80x2 are arranged in alternate positions in the column direction, and the electrodes Xxe2x80x2 and Yxe2x80x2 of each pair (Xxe2x80x2, Yxe2x80x2) face each other with a discharge gap gxe2x80x2 between. Each of the row electrode pairs (Xxe2x80x2, Yxe2x80x2) forms a display line (row) L in the matrix display.
The front glass substrate 1 is situated opposite a back glass substrate 4 with a discharge space Sxe2x80x2, filled with a discharge gas, interposed between the substrates 1 and 4. The back glass substrate 4 is provided thereon with: a plurality of column electrodes Dxe2x80x2 which are arranged parallel to each other and each extend in a direction at right angles to the row electrode pair (X, Y); band-shaped partition walls 5 each extending in parallel to and between the two column electrodes Dxe2x80x2; and phosphor layers 6 formed of phosphor materials of a red color (R), green color (G), and blue color (B), each of which covers the side faces of adjacent partition walls 5 and the column electrode Dxe2x80x2.
In each display line L, the partition walls 5 partition the discharge space Sxe2x80x2 into areas each corresponding to an intersection of the column electrode Dxe2x80x2 and the row electrode pair (Xxe2x80x2, Yxe2x80x2), to define discharge cells Cxe2x80x2 which are unit light-emitting areas.
Such surface-discharge-scheme alternating-current-type PDP generates images through the following procedure.
First, in an addressing period following a reset period for carrying out reset discharge, discharge is selectively caused between one of the row electrode pair (Xxe2x80x2, Yxe2x80x2) (the row electrode Yxe2x80x2 in this example) and the column electrode Dxe2x80x2 in each of the discharge cells Cxe2x80x2 (an addressing discharge). As a result of the addressing discharge, lighted cells (the discharge cell in which a wall charge is formed on the dielectric layer 2) and non-lighted cells (the discharge cell in which a wall charge is not formed on the dielectric layer 2) are distributed over the panel surface in accordance with an image to be displayed.
After completion of the addressing period, a discharge sustaining pulse is simultaneously applied alternately to the row electrodes Xxe2x80x2 and Yxe2x80x2 of each row electrode pair in each display line L. Every time the discharge sustaining pulse is applied, a sustaining discharge is caused between the row electrodes Xxe2x80x2 and Yxe2x80x2 in each lighted cell by the wall charge formed on the dielectric layer 2.
The sustaining discharge in each lighted cell causes ultraviolet rays to generate from a xenon gas included in the discharge gas. The generated ultraviolet rays excites the red (R), green (G) or blue (B) phosphor layer 6 in each lighted cell Cxe2x80x2 to thereby form a display image.
In the conventional three-electrode surface discharge scheme alternating current type PDP as described above, the addressing discharge and the sustaining discharge are produced in the same discharge cell Cxe2x80x2. Therefore, in each discharge cell Cxe2x80x2 the addressing discharge is initiated between the electrodes with the interposition of the red (R), green (G) or blue (B) phosphor layer 6 which is provided for emitting color when the sustaining discharge is caused.
For this reason, the addressing discharge produced in the discharge cell Cxe2x80x2 is subjected to influences ascribable to the phosphor layer 6, such as discharge properties varying with the phosphor materials of various colors forming the phosphor layers 6, variations in the thickness of layers produced when the phosphor layers 6 are formed in the manufacturing process, and the like. Hence, the conventional PDPs have a significant difficult problem for obtaining equal addressing discharge properties in each discharge cell Cxe2x80x2.
In the aforementioned three-electrode surface-discharge-scheme alternating-current-type PDP, a large discharge space in each discharge cell Cxe2x80x2 is needed for increasing the luminous efficiency. Therefore, the prior art employs the method of increasing the height of the partition wall 5.
However, if the partition wall 5 is increased in height for increasing the luminous efficiency, the interval between the row electrode Yxe2x80x2 and the column electrode Dxe2x80x2 between which the addressing discharge is produced is also increased. This increased interval produces a problem of an increase in a starting voltage for the addressing discharge.
Further, in the aforementioned three-electrode surface-discharge-scheme alternating-current-type PDP, the luminous efficiency of the PDP is enhanced by increasing the xenon-gas content in the discharge gas filling the discharge space Sxe2x80x2 to 10 percent or more, for example. However, if the xenon-gas content in the discharge gas is increased, a driving voltage for the addressing discharge and the sustaining discharge is also increased, leading to a problem of an increase in the electrical power consumption of the PDP.
The present invention has been made to solve the problems associated with the conventional surface-discharge-scheme alternating-current-type plasma display panel as described above.
Accordingly, it is a first object of the present invention to provide a surface-discharge-scheme alternating-current-type plasma display panel capable of stabilizing addressing discharge properties in each of discharge cells, and of enhancing luminous efficiency.
In addition to the first object, it is a second object of the present invention to provide a surface-discharge-scheme alternating-current-type plasma display panel capable of reducing driving voltage for an addressing discharge and a sustaining discharge.
To attain the first object, according to a first feature of the present invention, a plasma display panel including: a front substrate; a plurality of row electrode pairs arranged in a column direction on a back surface of the front substrate, and each extending in a row direction and forming a display line; a dielectric layer covering the row electrode pairs on the back surface of the front substrate; a back substrate placed opposite the front substrate with a discharge space interposed; and a plurality of column electrodes arranged in the row direction on a surface of the back substrate facing toward the front substrate, and each extending in the column direction to intersect the row electrode pairs and form unit light-emitting areas in the discharge space at the respective intersections, the plasma display panel comprises: partition walls surrounding each of the unit light-emitting areas to define the unit light-emitting areas; a dividing wall for dividing each of the unit light-emitting areas into a first discharge area facing mutually opposite parts of the respective row electrodes constituting each of the row electrode pairs and providing for a discharge produced between the mutually opposite row electrodes, and a second discharge area facing a part of one row electrode of the row electrodes initiating a discharge in association with the column electrode, and providing for the discharge produced between the column electrode and the part of the one row electrode; and a communicating element provided between the first discharge area and the second discharge area for communication from the second discharge area to the first discharge area.
In the plasma display panel in the first feature, when an image is generated, a discharge (addressing discharge) is caused between the column electrode and one of the row electrodes constituting each of the row electrode pairs, in the second discharge area (addressing discharge cell) formed in the unit light-emitting area divided off by the dividing wall. The discharge caused in the second discharge area is transferred through the communicating element provided between the first and second discharge areas, to the first discharge area, and spreads out into the first discharge area. Thus, the first discharge areas having a wall charge formed therein (lighted cells) and the first discharge areas having no wall charge formed therein (non-lighted cells) are distributed over the panel surface in accordance with the image to be generated.
After that, in each of the first discharge areas having the wall charge formed therein (lighted cells), another discharge (sustaining discharge) is caused between the mutually opposite parts of the respective row electrodes constituting each row electrode pair. Ultraviolet rays generated by the sustaining discharge excites phosphor layers of the three primary colors red (R), green (G) and blue (B) for emission of color light to form the image in response to an image signal on the panel surface.
According to the first feature, in this way, in order to distribute the unit light-emitting areas having the wall charge formed therein and the unit light-emitting areas having no wall charge formed therein over the panel surface, the addressing discharge is produced between the column electrode and one row electrode of the row electrode pair in a second discharge area, and the second discharge area is formed independently of the first discharge area in which the sustaining discharge is produced, after the completion of the addressing discharge, between the row electrodes constituting each of the row electrode pairs in order to emit light. For this reason, even if a discharge space of the first discharge area is designed to be larger for enhancement of the luminous efficiency of the plasma display panel and therefore a distance between the row electrode and the column electrode is increased, it is possible to place the column electrode in a position closer to the row electrode in the second discharge area than its position in the first discharge area, for a reduction in a starting voltage for the discharge between the column electrode and the row electrode. Thus, the enhancement of luminous efficiency and a reduction in a starting voltage for the discharge between the column electrode and the row electrode are attained at the same time.
Further, the independent design of the first discharge area for producing the discharge between the row electrodes of the row electrode pair and the second discharge area for producing the discharge between the column electrode and the row electrode, eliminates the need of forming a phosphor layer, emitting light by means of the discharge, in the second discharge area. The discharge caused between the column electrode and the row electrode in the second discharge area does not undergo the influences of the colors of phosphor materials forming the phosphor layers and the variations in the thickness of the phosphor layers, thus providing stabilized discharge properties between the column electrode and the row electrode.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a second feature in that each of the row electrodes constituting each of the row electrode pairs comprises an electrode body extending in the row direction, and transparent electrodes each protruding from the electrode body in the column direction in each unit light-emitting areas to face the other one of the row electrodes constituting the row electrode pair with a discharge gap between; and that the electrode body of at least one of the row electrodes is opposite the second discharge areas to allow the discharge to be caused between the electrode body and the column electrode in each second discharge area.
With the plasma display panel of the second feature, each of the row electrodes comprises the electrode body extending in the row direction and the transparent electrodes each connected to the electrode body in each of the unit light-emitting areas. The electrode body for initiating the discharge in association with the column electrode is positioned opposite the second discharge areas, so that an addressing discharge is produced between the electrode body and the column electrode in each of the second discharge areas.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a third feature in that each of the row electrodes constituting each of the row electrode pairs comprises an electrode body extending in the row direction, and transparent electrodes each protruding from the electrode body in the column direction in each unit light-emitting areas to face the other one of the row electrodes constituting the row electrode pair with a discharge gap between, and each having an extended part extending from the electrode body in the direction opposite to the transparent electrode of the other one of the row electrodes of the row electrode pair; and that the extended part of the transparent electrode of at least one of the row electrodes is opposite the second discharge area to allow the discharge to be caused between the extended part of the transparent electrode and the column electrode in the second discharge area.
With the plasma display panel of the third feature, the extended part is provided to each of the transparent electrodes which are each connected to the electrode body extending in the row direction in each unit light-emitting area and, form a row electrode together with the electrode body. The extended part extends from the connecting point of the transparent electrode with the electrode body in the direction opposite to a transparent electrode of the other one of the row electrodes paired, so as to be positioned opposite to the second discharge area. In this way, a discharge is produced between such an extended part and the column electrode in the second discharge area.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a fourth feature of further comprising an additional element jutting out from a part of the dielectric layer opposite each of the second discharge areas, in a direction of the second discharge area, and coming in contact with the partition walls defining the corresponding unit light-emitting area, to block the second discharge area from the unit light-emitting area adjacent thereto but not associated therewith.
With the plasma display panel of the fourth feature, the additional element is provided on the part of the dielectric layer covering the row electrode pairs opposite each of the second discharge areas, and in contact with the partition wall surrounding each of the unit light-emitting areas for dividing adjacent unit light-emitting areas off from each other. Due to such an additional element, a second discharge area formed in one unit light-emitting area is blocked off from an unconnected unit light-emitting area adjacent thereto. Thus the charged particles generated by the discharge between the column and row electrodes in the second discharge area, pass through the communicating element to flow into only the corresponding first discharge area of the unit light-emitting area concerned.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a fifth feature of further comprising a black or dark-colored light absorption layer provided on an area opposite each of the second discharge areas on the front substrate side.
With the plasma display panel of the fifth feature, a face of the second discharge area on the front substrate side, or on the display side, is covered with the black or dark-colored light absorption layer. The light absorption layer prevents the light generated by the discharge between the column and row electrodes in the second discharge area from leaking toward the display surface of the panel, and consequently from having an adverse effect on the image to be formed on the display surface of the panel. The light absorption layer also prevents the reflection of ambient light incident upon an area of the display surface of the panel oppose the second discharge area, thereby eliminating the possibility of an adverse effect upon the contrast in the image.
To attain the first object, a plasma display panel has, in addition to the configuration of the fifth feature, a sixth feature in that each of the row electrodes constituting each of the row electrode pairs comprises an electrode body extending in the row direction and transparent electrodes each protruding from the electrode body in the column direction in each unit light-emitting area to face the other one of the row electrodes constituting the row electrode pair with a discharge gap between; that the electrode body of at least one of the row electrodes is opposite the second discharge area to allow the discharge to be caused between the electrode body and the column electrode in the second discharge area; and that the light absorption layer is constituted by a black or dark-colored layer included in the electrode body of the row electrode, and a black or dark-colored layer formed in an area opposite to the second discharge area on the front substrate side.
With the plasma display panel of the sixth feature, each of the row electrodes comprises an electrode body extending in the row direction, and transparent electrodes each connected to the electrode body in each unit light-emitting area. The electrode body of the row electrode initiating the discharge in association with the column electrode is positioned opposite the second discharge area. Thus the discharge is produced between the electrode body and the column electrode in the second discharge cell.
The electrode body of the row electrode opposite to the second discharge area is formed of a black or dark-colored layer or is constructed partially of a black or dark-colored layer. Additionally, an area opposite to the second discharge area on the front substrate side in which the electrode bodies of the row electrodes are not formed is covered with a black or dark-colored layer. The provision of such black or dark-colored layers prevents the light generated by the addressing discharge between the column and row electrodes in the second discharge area from leaking toward the display surface of the panel, and consequently from having an adverse effect on the image to be formed on the display surface of the panel. In addition, the reflection of ambient light incident upon an area of the display surface of the panel opposite the second discharge area is prevented. As a result, the possibility of an adverse effect upon the contrast in the image is eliminated.
To attain the first object, a plasma display panel has, in addition to the configuration of the fifth feature, a seventh feature of further comprising an additional element jutting out from a part of the dielectric layer opposite each of the second discharge areas in a direction of the second discharge area, to come in contact with the partition walls defining the corresponding unit light-emitting area, to block the second discharge area from the unit light-emitting area adjacent thereto but not associated therewith, and formed of a black or dark-colored material to constitute the light absorption layer.
With the plasma display panel of the seventh feature, the additional element is provided on a part of the dielectric layer, overlying the row electrode pairs, opposite to each of the second discharge areas, and in contact with the partition wall surrounding each of the unit light-emitting areas for dividing adjacent unit light-emitting areas off from each other. Due to such an additional element, a second discharge area formed in one unit light-emitting area is blocked from an unconnected unit light-emitting area adjacent thereto, and thus the charged particles generated by the discharge between the column and row electrodes in the second discharge area pass through the communicating element to flow into only the corresponding first discharge area of the unit light-emitting area concerned. The additional element also constitutes the light absorption layer by being formed of the black or dark-colored material. Such a light absorption layer prevents the light generated by the discharge between the column and row electrodes in the second discharge area from leaking toward the display surface of the panel, and consequently from having an adverse effect on the image to be formed on the display surface of the panel, and it also prevents the reflection of ambient light incident upon an area of the display surface of the panel opposite the second discharge area, thereby eliminating the possibility of an adverse effect upon the contrast on the image.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, an eighth feature of further comprising a phosphor layer provided only in the first discharge area for emitting light by means of the discharge.
With the plasma display panel of the eighth feature, a phosphor layer for emitting light by means of the discharge is not provided in the second discharge area provided for producing an addressing discharge between the column electrode and the row electrode. Hence, the addressing discharge in the second discharge area is not subject to the disadvantageous influences of differences in discharge properties produced by phosphor materials in the three primary colors forming the phosphor layers and variations in the thickness of the phosphor layers, whereby the discharge properties of the addressing discharge in the second discharge area are stabilized.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a ninth feature of further comprising a protrusion element provided in an area opposite to the second discharge area on the back substrate side and between the back substrate and the column electrode, and protruding into the second discharge area in the direction of the front substrate, to allow a part of the column electrode opposite each of the second discharge electrodes to jut out in the direction of the front substrate.
With the plasma display panel of the ninth embodiment, in each of the second discharge areas, the column electrode is raised from the back substrate to be brought closer to the row electrode by the protrusion element formed between the back substrate and the column electrode. Accordingly, a discharge distance between the column electrode and the row electrode in the second discharge area is smaller than a distance between the column and row electrodes in the first discharge area. It is possible to reduce a starting voltage for the discharge by shortening the discharge distance between the column electrode and the row electrode in each of the second discharge areas, while the large discharge space in the first discharge area remains unchanged.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a tenth feature of further comprising a priming particle generating layer provided in each of the second discharge areas of the unit light-emitting areas.
With the plasma display panel of the tenth feature, prior to the addressing discharge between the column And row electrodes in the second discharge area, a reset discharge to form (or erase) a wall charge is produced in the first discharge area to allow xenon included in a discharge gas to radiate ultraviolet rays. The ultraviolet rays excite the priming particle generating layer formed in the second discharge area to allow it to radiate ultraviolet rays. The ultraviolet rays excites a protective layer overlying the dielectric layer and the like to allow them to emit priming particles. Due to the afterglow characteristic of the priming particle generating layer, a sufficient quantity of the priming particles required for producing the addressing discharge is ensured in the second discharge area during the period of the addressing discharge in the second discharge area, resulting in prevention of the occurrence of a false discharge or a discharge time lag incident to a decrease in the priming particle quantities with the passage of time after the completion of the reset discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the tenth feature, an eleventh feature in that the priming particle generating layer is formed of a ultraviolet-region light emissive material having an afterglow characteristic of continuously radiating ultraviolet rays when the material is excited by ultraviolet rays having a predetermined wavelength.
With the plasma display panel of the eleventh feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area. In turn, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the eleventh feature, a twelfth feature in that the ultraviolet-region light emissive material has an afterglow characteristic for 0.1 msec or more.
With the plasma display panel of the twelfth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area. Additionally, the afterglow characteristic continues for 0.1 msec or more. As a result, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is fully prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the eleventh feature, a thirteenth feature in that the ultraviolet-region light emissive material has an afterglow characteristic for 1 msec or more.
With the plasma display panel of the thirteenth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area. Further, the afterglow characteristic continuing for 1 msec or more provides the priming particle quantities needed roughly for the duration of the addressing discharge. Thus, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is further fully prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the eleventh feature, a fourteenth feature in that the priming particle generating layer includes a material having a work function of 4.2 eV or less.
With the plasma display panel of the fourteenth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer, allows the excited material having a work function of 4.2 eV or less (high xcex3 material) which is included in the priming particle generating layer, to continuously emit priming particles. Hence, when the addressing discharge is produced between the column and row electrodes in the second discharge area, a decrease in quantity of the priming particles with the passage of time is prevented, to provide a sufficient quantity of the priming particles needed for the addressing discharge. In turn, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a fifteenth feature of further comprising a dielectric layer, formed of a material having a relative permittivity of 50 or more, provided in a position in each of the second discharge areas on the back substrate side in a form of being interposed between the column electrode and the part of the one row electrode initiating the discharge in association with the column electrode.
With the plasma display panel of the fifteenth feature, the dielectric layer having a relative permittivity of 50 or more is provided in each second discharge area, and shortens an apparent discharge distance between the column electrode and the row electrode in the second discharge area, thereby successfully reducing a starting voltage for the addressing discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a sixteenth feature in that the communicating element is constituted by a clearance formed between the front substrate and the dividing wall by determining a height of the dividing wall dividing off the first discharge area and the second discharge area in each unit light-emitting area to be less than a height of the partition walls for defining the periphery of the unit light-emitting area.
With the plasma display panel of the sixteenth feature, even if a partition wall for defining the periphery of each unit light-emitting area is in contact with a part of a dielectric layer or the like provided on the front substrate to block adjacent unit light-emitting areas from each other, since the communication element is provided by the clearance which is formed between the dividing wall having a height less than that of the partition wall and dividing off the first discharge area and the second discharge area, and a part of the dielectric layer or the like provided on the front substrate, the charged particles generated by the discharge in the second discharge area are allowed to pass through the communicating element to flow into the first discharge area.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a seventeenth feature in that the communicating element is constituted by a groove formed in the dividing wall dividing off the first discharge area and the second discharge area, and having both ends opening toward the first discharge area and the second discharge area.
With the plasma display panel of the seventeenth feature, even if a partition wall for defining the periphery of each unit light-emitting area is in contact with a part of the dielectric layer or the like provided on the front substrate to block adjacent unit light-emitting areas from each other, since the communication element constituted by the groove which is formed in the dividing wall dividing off the first and second discharge areas permits communication from the second discharge area to the first discharge area, the charged particles generated by the discharge in the second discharge area pass through the communicating element to introduce into the first discharge area.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, an eighteenth feature of further comprising an additional element jutting out from a part of the dielectric layer opposite each of the second discharge areas in a direction of the second discharge area, to come in contact with the partition walls defining each of the unit light-emitting areas, to block the second discharge area from the unconnected unit light-emitting area adjacent thereto, and the communicating element is formed in the additional element.
With the plasma display panel of the eighteenth feature, when the additional element jutting out from the dielectric layer in the direction of the back substrate is in contact with the partition wall for defining the periphery of each unit light-emitting area and the dividing wall for dividing off the first and second discharge areas, the communicating element formed in the additional element permits communication from the second discharge area to the first discharge area. Thus, the charged particles generated by the discharge in the second discharge area are introduced through the communication element into the first discharge area.
To attain the first object, a plasma display panel has, in addition to the configuration of the first feature, a nineteenth feature of further comprising either a high relative permittivity dielectric layer formed of a material having a required relative permittivity, or a conductor layer formed of an electrically-conductive material, provided on the back substrate in each of the second discharge areas.
In the plasma display panel of the nineteenth feature, either the high relative permittivity dielectric layer or the conductor layer provided in each of the second discharge areas decreases a discharge distance between the column electrode and the part of one row electrode of the paired row electrodes between which the addressing discharge is caused. Hence, the addressing discharge is started at a low discharge-starting voltage.
According to the nineteenth feature, even when a distance between the row electrode and the column electrode is increased by increasing a discharge space of the first discharge area for enhancement of the luminous efficiency of the plasma display panel, a discharge distance between the column electrode and one of the row electrodes in each of the second discharge areas is shortened by providing either the high relative permittivity dielectric layer or the conductor layer in each of the second discharge areas. Thus, a reduction in a starting voltage for the addressing discharge and the enhancement of luminous efficiency are attained at the same time.
To attain the first object, a plasma display panel has, in addition to the configuration of the nineteenth feature, a twentieth feature in that the material forming the high relative permittivity dielectric layer has a relative permittivity of 50 or more.
With the plasma display panel of the twentieth feature, the addressing discharge is produced between the column and row electrodes with the interposition of the dielectric layer having a relative permittivity of 50 or more in each of the second discharge areas. This design decreases an apparent discharge distance of the addressing discharge between the column electrode and the row electrode, so as to reduce a starting voltage for the addressing discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the nineteenth feature, a twenty-first feature in that the second discharge area is further divided into a first area positioned between the column electrode and the part of the one row electrode initiating the discharge in associated with the column electrode, and a second area having the area of the second discharge area with the exception of the first area, and either the high relative permittivity dielectric layer or the conductor layer is formed in the first area of the second discharge area.
With the plasma display panel of the twenty-first feature, the second discharge area is divided into the first area and the second area, and the high relative permittivity dielectric layer or the conductor layer is formed only in the first area which is positioned between the column electrode and the row electrode initiating the discharge in association with the column electrode. That is, a dielectric layer is not provided in an area unnecessary to start the addressing discharge. As a result, the plasma display panel is prevented from having an undesired interelectrode capacitance between adjacent column electrode, and consequently from having a reactive power.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-first feature, a twenty-second feature of further comprising a priming particle generating layer provided in the second area of each of the second discharge areas.
With the plasma display panel of the twenty-second feature, prior to the addressing discharge between the column and row electrodes in the second discharge area, a reset discharge is produced in the first discharge area to allow xenon included in a discharge gas to radiate ultraviolet rays. The ultraviolet rays excite the priming particle generating layer formed in the second area of the second discharge area to allow it to radiate ultraviolet light. The ultraviolet light excites a protective layer overlying the dielectric layer and the like to allow them to emit priming particles. Due to the afterglow characteristic of the priming particle generating layer, a sufficient quantity of the priming particles required for producing the addressing discharge is ensured in the second discharge area during the period of the addressing discharge in the second discharge area, resulting in prevention of the occurrence of a false discharge or a discharge time lag incident to a decrease in the priming particle quantities with the passage of time after the completion of the reset discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-second feature, a twenty-third feature in that the priming particle generating layer is formed of a ultraviolet-region light emissive material having an afterglow characteristic of continuously radiating ultraviolet rays when the material is excited by ultraviolet rays having a predetermined wavelength.
With the plasma display panel of the twenty-third feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area. In turn, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-third feature, a twenty-fourth feature in that the ultraviolet-region light emissive material has an afterglow characteristic for 0.1 msec or more.
With the plasma display panel of the twenty-fourth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area.
Further, the afterglow characteristic continues for 0.1 msec or more. As a result, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is fully prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-third feature, a twenty-fifth feature in that the ultraviolet-region light emissive material has an afterglow characteristic for 1 msec or more.
With the plasma display panel of the twenty-fifth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer prevents a decrease in quantity of the priming particles with the passage of time when the addressing discharge is produced between the column and row electrodes in the second discharge area.
Additionally, the afterglow characteristic continuing for 1 msec or more provides the priming particle quantities needed roughly for the duration of the addressing discharge. Thus, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is further fully prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-second feature, a twenty-sixth feature in that the priming particle generating layer includes a material having a work function of 4.2 eV or less.
With the plasma display panel of the twenty-sixth feature, the afterglow characteristic of the ultraviolet-region light emissive material forming the priming particle generating layer, allows the excited material having a work function of 4.2 eV or less which is included in the priming particle generating layer, to continuously emit priming particles. Hence, when the addressing discharge is produced between the column and row electrodes in the second discharge area, a decrease in quantity of the priming particles with the passage of time is prevented, to provide a sufficient quantity of the priming particles needed for the addressing discharge. In turn, the occurrence of a false discharge or a discharge time lag incident to a decrease in priming particle quantities is prevented.
To attain the first object, a plasma display panel has, in addition to the configuration of the nineteenth feature, a twenty-seventh feature of further comprising a high relative permittivity dielectric layer provided on a face, facing the front substrate, of the conductor layer formed in each of the second discharge areas.
With the plasma display panel of the twenty-seventh feature, a discharge distance of the addressing discharge produced between the column electrode and one row electrode of the paired row electrodes in the second discharge area is shortened by the conductor layer formed in the second discharge area, and therefore a starting voltage for the addressing discharge is decreased. An apparent discharge distance between the conductor layer and the one row electrode is decreased by the high relative permittivity dielectric layer formed on the face of the conductor layer, and therefore a starting voltage for the addressing discharge is further decreased.
To attain the first object, a plasma display panel has, in addition to the configuration of the nineteenth feature, a twenty-eighth feature in that the conductor layer is formed on a column-electrode protective layer covering the column electrodes, and is electrically connected to the column electrode through a conducting element with the interposition of the column-electrode protective layer.
With the plasma display panel of the twenty-eighth, due to the electrical connection between the conductor layer and the column electrode through the conducting element with the interposition of the column-electrode protective layer, a discharge distance between the column electrode and one row electrode of the paired row electrodes is further decreased, to significantly reduce a starting voltage for the addressing discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the twenty-eighth feature, a twenty-ninth feature in that the conducting element electrically connecting the conductor layer to the column electrode is a through hole formed in the column-electrode protective layer.
With the plasma display panel of the twenty-ninth feature, the conductor layer and the column electrode are electrically connected by the through hole, formed in the column-electrode protective layer, with the interposition of the column-electrode protective layer concerned, whereby a discharge distance between the column electrode and one row electrode of the paired row electrodes is further decreased, resulting in a significant decrease of a starting voltage for the addressing discharge.
To attain the first object, a plasma display panel has, in addition to the configuration of the nineteenth feature, a thirtieth feature in that the one row electrodes and the other row electrodes constituting the row electrode pairs are arranged in alternate positions in each display line in the column direction such that the one row electrodes of the adjacent row electrode pairs are arranged back to back and the other row electrodes of the adjacent row electrode pairs are arranged back to back; that either the high relative permittivity dielectric layer or the conductor layer is formed in the second discharge area opposite to the parts of the back-to-back one row electrodes individually causing the discharge in association with the column electrode; and that a space formed between either the high relative permittivity dielectric layer or the conductor layer and the dielectric layer covering the row electrode pairs, is divided by a rib member extending in the row direction into areas respectively facing the parts of the one row electrodes arranged back to back.
With the plasma display panel of the thirtieth feature, in the arrangement of the row electrodes of two kinds consisting the row electrode pairs, the row electrodes of the same kind of the respective row electrode pairs adjacent to each other are arranged back to back in the column direction. Due to such an arrangement, discharge capacity is not formed in the non-display area between the row electrodes positioned back to back when a discharge sustaining pulse is applied across the row electrode pair and the sustaining discharge is initiated between the row electrodes, resulting in prevention of reactive power.
To attain the second object, a plasma display panel has, in addition to the configuration of the first feature, a thirty-first feature in that parts of the row electrodes, constituting each of the row electrode pairs, for initiating the discharge therebetween, are opposite each other with an empty space between.
With the plasma display panel of the thirty-first feature, in a position opposite to a first discharge area in which the wall charge is formed by the addressing discharge produced in the second discharge area (a lighted cell), a discharge (sustaining discharge) is caused between the opposite parts of the row electrodes of the row electrode pair with the interposition of an empty space which is formed between the parts of the row electrodes concerned. Ultraviolet rays generated by the sustaining discharge excite the phosphor layer of a red (R), green (G) or blue color (B) of the three primary colors formed in each of the first discharge areas to allow it to emit light. An image is thus formed on the panel surface in response to an image signal.
According to the thirty-first feature, due to the design in which the sustaining discharge is caused between the opposite parts of the row electrodes of the row electrode pair with the interposition of the empty space which is formed between the opposite parts concerned, a distance of an electric line force passing through the inside of the dielectric layer when the sustaining discharge is caused is shortened, and therefore the electric field strength of the electric line force is increased considerably more than that in the prior art. For this reason, even when a xenon-gas content in the discharge gas is increased for enhancement of the luminous efficiency of the sustaining discharge, it is possible to produce the discharge at a low driving voltage.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-first feature, a thirty-second feature in that the empty space is constituted by a recess formed in a part of the dielectric layer positioned between the parts of the row electrodes initiating the discharge therebetween.
With the plasma display panel of the thirty-second feature, the recess is formed in a part of the dielectric layer positioned between the parts of the row electrodes of the row electrode pair initiating the discharge therebetween, and an empty space in the recess is interposed between the opposite parts of the row electrodes causing the sustaining discharge.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-second feature, a thirty-third feature in that the recess is formed in an island-like form in each of the first discharge areas.
With the plasma display panel of the thirty-third feature, the recess interposed between the parts of the row electrodes causing the sustaining discharge therebetween is formed independently in a circular- or quadrangular-shaped island form in each first discharge area.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-second feature, a thirty-fourth feature in that the recess is formed in a band shape extending in the row direction and continuing between the first discharge areas adjacent to each other in the row direction.
With the plasma display panel of the thirty-fourth feature, the recess interposed between the parts of the row electrodes of the row electrode pair causing the sustaining discharge therebetween has a band shape extending in the row direction, and is formed in such a manner as to span adjacent first discharge areas in the row electrode.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-first feature, a thirty-fifth feature in that the parts of the row electrodes constituting each of the row electrode pairs for initiating the discharge therebetween are opposite each other in a face-to-face form.
In the plasma display panel of the thirty-fifth feature, the part of each of the row electrodes of the row electrode pair between which the sustaining discharge is caused is shaped by, for example, being bent in a direction of either the front substrate or the back substrate in relation to a part of its row electrode extending in parallel to the front substrate, so that the parts of the both the row electrodes are opposite each other in a face-to-face form.
With this design, when compared to a conventional case where a sustaining discharge is produced between parts of the row electrodes which are end-to-end with each other, an electric line force of the sustaining discharge passes through a decreased discharge-distance, so that the electric field strength thereof is increased. For this reason, even in the use of a discharge gas with a high xenon-gas content, it is possible to further reduce driving voltage required for causing the sustaining discharge.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-first feature, a thirty-sixth feature in that each of the row electrodes constituting each of the row electrode pairs comprises an electrode body extending in the row direction, and transparent electrodes each protruding from the electrode body in the column direction in each unit light-emitting areas to face the other one of the row electrodes constituting the row electrode pair with a discharge gap between; and that the electrode body of at least one of the row electrodes is opposite the second discharge areas to allow the discharge to be caused between the electrode body and the column electrode in each second discharge area.
With the plasma display panel of the thirty-sixth feature, each of the row electrodes comprises the electrode body extending in the row direction and the transparent electrodes each connected to the electrode body in each of the unit light-emitting areas. The electrode body for initiating the discharge in association with the column electrode is positioned opposite the second discharge areas, so that an addressing discharge is produced between the electrode body and the column electrode in each of the second discharge areas.
To attain the second object, a plasma display panel has, in addition to the configuration of the thirty-first feature, a thirty-seventh feature in that each of the row electrodes constituting each of the row electrode pairs comprises an electrode body extending in the row direction, and transparent electrodes each protruding from the electrode body in the column direction in each unit light-emitting areas to face the other one of the row electrodes with a discharge gap between, and each having an extended part extending from the electrode body in the direction opposite to the transparent electrode of the other one of the row electrodes of the row electrode pair; and that the extended part of the transparent electrode of at least one of the row electrodes is opposite the second discharge area to allow the discharge to be caused between the extended part of the transparent electrode and the column electrode in each second discharge area.
With the plasma display panel of the thirty-seventh feature, the extended part is provided to each of the transparent electrodes which are each connected to the electrode body extending in the row direction in each unit light-emitting area and form a row electrode together with the electrode body. The extended part extends from the connecting point of the transparent electrode with the electrode body in the direction opposite to a transparent electrode of the other one of the row electrodes paired, so as to be positioned opposite to the second discharge area. In this way, a discharge is produced between such an extended part and the column electrode in the second discharge area.
These and other objects and advantages of the present invention will become obvious to those skilled in the art upon review of the following description, the accompanying drawings and appended claims.